Pakistani Christians stage a protest on Sept. 22, 2013, in Lahore against the killing of their community members in twin suicide bomb attacks on a historic church in Peshawar.

Christians took to the streets throughout Pakistan Monday to denounce the killing of at least 81 people in a church bombing on Sunday.

The attack, carried out by a pair of suicide bombers, wounded at least 120 people, in addition to the 81 killed. The bombing of a historic church in Peshawar is now Pakistan's deadliest-ever attack on the country's Christian minority.

Large demonstrations shook Peshawar on Monday, with rallies also reported in the Pakistani cities of Islamabad, Karachi, Lahore, Multan, Faisalabad, Gujranwala, Hyderabad and Quetta, according to reports.

Many are angered by the perceived widespread lack of security in Pakistan. "Our state and our intelligence agencies are so weak that anybody can kill anyone anytime," Paul Bhatti, the head of the All Pakistan Minorities Alliance, told the Associated Press on Monday.

In Peshawar, where protests reportedly turned violent, demonstrators blocked roads with the bodies of the victims, according to IANS.

Burials have also been taking place for the victims of the twin blasts. Hundreds of women were seen clutching coffins and sobbing, while men hugged and cried, and children looked on in confusion.

The attacks on Sunday occurred as hundreds of worshipers were leaving the historic white-stone All Saints Church in the Kohati Gate district Sunday morning.

“What have we done wrong to these people,'” asked one of the wounded, John Tariq, who lost his father in the bombings. “Why are we being killed?"

An offshoot of the Pakistani Taliban has taken responsibility for the attack, offering the following explanation: "Until and unless [US] drone strikes [in Pakistan] are stopped, we will continue to strike wherever we will find an opportunity against non-Muslims," said Ahmed Marwat, a spokesman for Tehrik-e-Taliban Pakistan-Jandullah, according to Agence-France Press.

The majority of Pakistanis oppose such strikes, and the issue has strained US-Pakistani relations. Meanwhile, the main Taliban group in Pakistan, Tahrik-e-Taliban Pakistan, issued a statement saying they "refuse to take responsibility" for the church bombings, reported CNN.

Christians make up about four percent of Pakistan's 180 million people.

They tend to keep a low profile in the predominantly Muslim country, and while attacks on Christian areas occur sporadically, Sunday's bombings were among the deadliest in the country's recent history.

Religious violence and attacks on security forces have been on the rise in Pakistan in recent months as Prime Minister Nawaz Shariff attempts to tame insurgent forces after coming to power in June.